1. Technical Field
The present invention relates to a friction stir joining method, a structure body manufactured according to a friction stir joining method, a hollow frame member carried out a friction stir joining method, and a connection member for a hollow frame member carried out a friction stir joining method.
For example, the present invention is suitable for a friction stir joining method, a structure body manufactured according to a friction stir joining method of an aluminum alloy made extruded frame member which is used in a railway vehicle or a building structure and the like, a hollow frame member carried out a friction stir joining method, and a connection member body for a hollow frame member carried out a friction stir joining method.
2. Prior Art
A friction stir joining method is a method in which by rotating a round rod (it is called as "a rotary tool") which is inserted into a joining portion and moving the rotary tool along to a joining line of extruded frame members, and the joining portion is heated, softened and plastically fluidized and solid-stately joined.
The rotary tool is comprised of a small diameter portion which is inserted into the joining portion and a large diameter portion which is positioned at an outside portion of the small diameter portion of the rotary tool. The small diameter portion of the rotary tool and the large diameter portion of the rotary tool have the same axis. A boundary between the small diameter portion of the rotary tool and the large diameter portion of the rotary tool is inserted a little into the joining portion. The above stated technique is disclosed, for example in Japanese application patent laid-open publication No. Hei 9-309164 (EP 0797043 A2).
In FIG. 9 of this document of Japanese application patent laid-open publication No. Hei 9-309164 (EP 0797043 A2), a joining of two faces of the hollow extruded frame members is carried out from one face of the two faces of the hollow extruded frame member. Namely, a plate of one side face is abutted and from another face side of the another plate a friction stir joining is carried out. An outer face side of the plate is joined flatly. An end portion of the plate of the another face side is orthogonal to a thickness direction.
As shown in FIG. 9 of the above stated document of Japanese application patent laid-open publication No. Hei 9-309164 (EP 0797043 A2), a case where a hollow frame member is carried out from a face of one side according to the friction stir joining. In this case, it is important that an interval of plates 33 and 33 of upper faces of two hollow frame members 31 and 32 and an accuracy of a width of a coupling member 60 which is arranged this portion.
Both ends of the coupling member 60 are abutted to the plates 33 and 33 and are joined. For this reason, when the interval of the upper face plates 33 and 33 is smaller than a width of the coupling member 60, it is impossible to arrange the coupling member 60.
In reversibly, when the interval of the upper face plates 33 and 33 is larger than the width of the coupling member 60, it is difficult to carry out the friction stir joining to the abutted portion. Namely, it is important that a gap of the abutted portion formed between the plate 33 and the coupling member 60 is small.
However, in accordance with a manufacturing tolerance during a press-out processing of the hollow frame members 31 and 32 and the coupling member 60 and a manufacturing tolerance during the friction stir joining, to the abutted portion a large gap can occur easily. In a case of the joining of the car body of the railway vehicle, the above large gap is remarkable in the case in which many hollow frame members are joined by putting them side by side.